Brake Pads - Replacing the organic pads with sintered ones

I've just replaced the rear brake pads again - after around 2,500 miles. This leads us to a valuable GP800 ownership lesson - on a bike with a 6,000 mile service interval.

I was cutting it fine (although not as badly as last time !). The pads would have been replaced at the recent 18,000 mile service but that would have pushed the job into a second day - and I wanted the bike back so I sourced and replaced them myself.

Although the more visible front calipers are the excellent Brembo "Serie Oro" jobs, the rear has to make do with the same Heng Tong caliper fitted to many of Piaggio's mopeds and small scooters.

This does have the advantage of ready availability (SFA353 if you're interested) but it also means that the common availability is limited to the lower grade organic pads which are fine for smaller bikes. These are what I fitted last time and to be fair, their ability to assist in bringing the 260kg behemoth down from very high speeds is not in question. If you read up on them, you'll also find plenty of recommendations based on the "feel" of the brakes. That's probably a fair point as I have locked up the rear of the GP800 far less frequently since fitting these pads. They also wear the disc itself far less.

Given the reputation of the Heng Tong caliper for seizing the retaining pins, a more frequent need to change pads (and re-apply copious quantities of Copaslip) could be seen as a positive benefit - but on December 5th, in our current weather conditions, that's not a positive feature in my book.

In fact, changing the pads is a remarkably straightforward job. I'm never entirely happy changing pads with the caliper hanging off the hydraulic line - especially if any force has to be applied (changing pads on the Brembo calipers fitted to the K75 is a much simpler proposition altogether) but once the retaining pins are unscrewed, the new pads just drop in - and at least small pistons are much easier to push back in to refit the caliper over the disc.

The new pads are EBC HH sintered pads. Lets hope that they last significantly longer - but not at a cost in increased "grabiness". The other thing that might encourage me to stick to the softer pads will be if I see any signs of increasing disc wear.

Chain oilers again – what goes around……..

If you look at the “Tutoro” tag, you’ll find the old post where I fitted the chain oiler in the first place. As an inveterate “fiddler” I wanted to improve it somehow – and I have always been drawn to the other inexpensive chainoiler, the Loobman. As it is sub £20 I bought a Loobman anyway. As many reviews will confirm, the delivery method to the chain is a little “Heath Robinson” but the way the bottle delivers a measured amount of oil is quite neat. The Tutoro reservoir was fitted quite high on the bike so I fitted the Loobman bottle low down behind the passenger footpeg giving me a much shorter “run” of tubing. What’s more, as the Tutoro delivery system was working fine I left it in place and ended up with a hybrid system of Loobman reservoir and Tutoro pipework.

This was my working system for a month or so and it was fine – at least until the bottle fell off to be lost forever somewhere between Dunstable and Newbury. Rather than returning to the Tutoro reservoir, I decided to give up on chain oilers and simply reverted to spraying chain lube at intervals. I had plenty of the white chain wax from before I'd fitted the Tutoro so that was sprayed liberally over the chain

One of the things that has always plagued me with my GP800 has been “noises off”. However sweet the engine is, I have always suffered from driveline noises of one kind or another. There was the dreaded “Strangled Sealion” noise ( I credit the X9 Owners Club for the phrase – I note a post on Modern Vespa forum that failed to do so !) which in my case was caused by a loose clutch nut and there is also chain noises which have been the bane of my life.

Soon after the events above, I noticed more driveline noises. It was a graunchy rotating noise and quite frankly sounded expensive and definitely mechanical – like a bearing about to give up. I posted on a thread on the GP800 sub forum at X9 Owners Club and found that the final drive pinion oil level may not have been topped up properly at service (thanks JimC). A quick removal of the passenger footrest and a squirt of gear oil from a childs medicine syringe cured that one (the level was a little low) but the graunchy grind was still present.

In a fit of desperation, I slackened the chain (way more than recommended) to see if reducing the strain on the driveline made any difference to the noise – surprisingly it did, but not by a lot. By now I was resigned to taking it somewhere with a blank cheque but as a final thought, I completely cleaned the chain removing all the white chain wax and manually lubricated the chain with Scottoiler oil that I used in the Loobman. This time I re-adjusted the chain correctly to spec.

Result – silence J

Well almost – it still clanks a bit when being pushed backwards but the horrible mechanical grating has gone. Even now, a few days later, I struggle to comprehend how something as basically simple as a stiff chain could make such a terminal sounding noise. I’m guessing that over time, the chain has stretched slightly unevenly and this will be cured by the (scarily expensive) chain replacement at the next service (18,000 miles).

Either way, I should have listened to myself by re-reading my earlier post (18^th Feb 2009) when I recommended against wax type chain lube – So here it is again – for me as much as any other GP800 owners out there

DON’T USE WAX TYPE CHAIN LUBE ON A GP800

Of course, YMMV, FWIW, IMHO, IANAL, ROFL, ETC and I may not have helped matters by either using too much of the white chain wax, or layering it up over time by not cleaning off the old wax before re-applying- but the advice above stands.

So, it's back to the Tutoro reservoir. fitted lower down where the Loobman bottle lived - which gives a much shorter tube run an d reduces the headache of priming. Even if you allow the oil to run out, the total amount of oil in the system is much less and just refilling the reservoir self-primes quite happily.

Listening to a GP800 provides the best way of knowing when it’s “right and tight”. If you close the throttle from about 35-40mph, as the speed falls away, between 30mph and 20mph the engine becomes almost inaudible and the only noise you can hear sounds like a coasting London Underground (tube) train. Of course if you’re not a Londoner that will be meaningless to you – but the noise is quite distinct, a comforting “whirring” sound.

As an aside, the noises from the rear were so severe that they masked another new noise that I’m ashamed to say I missed. I had always been surprised by the fact that my rear pads had never been replaced as I tend to favour the rear brake (despite it being the naturally clutch side for me). I had even unequally adjusted the lever reach to try to force me to split my braking in favour of the front brakes.

The pads have been replaced now !

Although I was concerned at the possibility that the allen keyed pins might have seized necessitating calliper replacement (eek – thanks again JimC) the task was remarkably straightforward – especially since I was suffering from “Housemaids Knee” at the time. I guess that’s testament to the original Thomsons quality of PDI which involved a great deal of dismantling and Copaslip before I took delivery. Not quite “BMW Brembo” simples but no real grief. The only problem was that the hole in the inner pad for the pin to slide through was slightly too small (probably by the thickness of its paint) requiring a simple ream out by hand with a drill bit.

Whew, that’s a long entry. I really must get round to updating this blog more often.